Conservative media are claiming that President Bill Clinton enacted a policy that bans guns at military bases in the wake of the mass shooting at a military facility in Chattanooga, Tennessee. In fact, the policy was enacted in 1992 during the administration of George H.W. Bush and does allow guns to be carried on base under some circumstances.

Fox News pundits repeatedly pushed -- and then walked back -- a false narrative propagated by an anti-Islam blogger that an "ISIS-linked" Twitter account warned of the Tennessee shooting prior to the attack.

UPDATE: Fox Admits It Was Wrong About ISIS Tweet

Fox News reported that an "ISIS-linked" Twitter account warned of today's shooting in Tennessee before it happened, but the tweet in question was sent after the attack had ended. The falsehood was propagated by anti-Islam blogger Pamela Geller before spreading through conservative media

Four Marines were killed when a shooter fired on two military sites in Chattanooga, Tennessee. Fox News reported that the attacks may be connected to ISIS because an ISIS supporter purportedly discussed the shooting on Twitter before it happened. Fox host Sean Hannity repeated the false claim on his radio show.

In fact, the tweet Fox News referenced was posted well after the shooting had already occurred. Mashable editor Brian Ries first pointed out the discrepancy.

On Your World, Fox's chief intelligence correspondent Catherine Herridge reported, "the last investigative thread I would mention at this point is that we're taking a hard look at a Twitter account -- an ISIS-linked Twitter account -- that seemed to have foreknowledge of the shooting in Chattanooga. The tweet went out at 10:34 with the hashtag Chattanooga referring to American dogs and a likely shooting. This of course was about 15 minutes before the shooting took place."

On his radio show, Fox News host Sean Hannity also referenced the inaccurate information.

HANNITY: We have a report from Robert Spencer's Jihad Watch, that he's put together -- a timeline regarding today's, what they are now calling a domestic terrorist act in Chattanooga. We have four Marines that have been killed. By the way, our thoughts, our prayers are with the families and the entire military community there. According to the AP, the shooting started around 10:30, 10:45. The Islamic State tweeted a warning about the attack, posted at 10:34 a.m. The ISIS tweet specifically mentioned Chattanooga, which is an obvious reference to the attack. If it's true that ISIS was taking credit for the shooting at the exact same time, or maybe slightly before the shooting commenced, that would be pretty strong evidence of a connection. And Spencer reminds us the Islamic State has called on Muslims to murder American military personnel here in the U.S.

Fox repeated the claim in further segments on Your World,The Five, and later on Special Report.

The source of the claim is conservative blogger Pamela Geller, who has a long history of anti-Muslim activism.

Geller made the claim on Twitter and on her blog, writing, "This morning an ISIS supporter tweeted this at 10:34 am -- the shooting started at 10:45." The report cited by Hannity from Jihad Watch cites Geller as the source. Spencer has often worked with Geller on anti-Muslim projects.

But the tweet was posted at 1:34 p.m. Eastern time, not 10:34 a.m., as Geller asserted. According to news reports, the shooting "unfolded at two sites over 30 minutes" and started "around 10:45 a.m. ET."

The image of the tweet she references on her blog appears to be stamped with the Western time zone -- Twitter time stamps are based on the user's time zone, not the time zone of the person who made the tweet.

Media Matters took this screenshot of the ISIS supporter's Twitter account at 5:13 p.m. ET, and it shows that the post was made 4 hours previously (near the 1 o'clock hour Eastern time).

Conservative blog Weasel Zippers also made the erroneous conclusion about the tweet in a post headlined, "Islamic State Account Tweets Warnings About Chattanooga Moments Before Shooting Began."

UPDATE: After this story was published, Fox News began to pull back on their allegation. From Special Report with Bret Baier:

BRET BAIER: Let me be careful about the tweet to the ISIS-related account. In Garland, Texas we know that it came out before the shooting, before that happened. In this case, the time stamp does say 10:34, but we don't know if that's Pacific time, Mountain time, Eastern time, so we have to be careful about it coming out before the shooting. Point is there are ISIS accounts that are pointing directly to this incident and touting it as one of own.

UPDATE #2: On TheO'Reilly Factor, this story was addressed at least three more times.

At the top of the Factor, O'Reilly reported the "sensational" ISIS tweet story, even after admitting it wasn't "exactly clear whether it's accurate."

Midway through the show, Catherine Herridge reappeared and admitted that "there are now some questions about the time stamp on one of the ISIS tweets earlier today." When O'Reilly pressed her on how she learned about the tweet, she said, "I first saw it this afternoon, it was part of the social media that was circulating."

At the end of the Factor, Special Report anchor Bret Baier clarified the timing of the tweet, saying that "all indications now are that it came out after the attack." When O'Reilly asked if that meant the ISIS tweet story was "a bogus situation," Baier replied, "yeah."

On the May 6 edition of his Fox News show, Hannity hosted Pamela Geller and Anjem Choudary to discuss Geller's anit-Islam cartoon contest in Garland, TX, the scene of a shooting on May 3. Choudary said he supports the death penalty for those who draw cartoons of the prophet Muhammad and for people who leave Islam. Geller claimed President Obama has "created an environment that raised the stakes" on terror in the United States.

Choudary is a radical Islamic preacher from the United Kingdom, and has links to Britons who have fought in Syria for the Islamic State. The advocacy group Hope Not Hate has described Choudary as "the single biggest gateway to terrorism in recent British history," saying he has "facilitated or encouraged" many Muslims to join the anti-Assad militants in Syria. Muslim groups in the United Kingdom have also denounced Choudary. The Muslim Council of Britain called him "a self-serving publicity seeker," and the Islamic Society of Britain said Choudary "has no legitimacy in the Muslim community."

Despite Choudary's clearly extreme views -- for example, he described ISIS leader Abu Bakr al-Baghdadi as "the caliph of all Muslims and the prince of the believers"-- Hannity has repeatedly invited him onto his show. In January, Hannity hosted Choudary to discuss the Charlie Hebdo shootings.

Pamela Geller is an extreme anti-Muslim activist who runs the American Freedom Defense Initiative, an organization designated as a hate group by the Southern Poverty Law Center. The Norwegian terrorist Anders Breivik cited her work frequently in his "manifesto." She has claimed that President Obama has "sided with" terrorists and warned that teaching Arabic in US schools was the "spearhead of an ideological project that is deeply opposed to the United States of America." In 2010, she campaigned against the so-called "Ground Zero mosque," which she described as a "triumphal mosque" on "conquered lands."

In an email to Media Matters, Heidi Beirich, the director of the SPLC's Intelligence Project, said of the segment:

"We're disappointed, but not entirely surprised, that Sean Hannity would offer a national platform to two well-known haters. Ms. Geller and Mr. Choudary represent nothing more than an extreme political fringe. Their divisive behavior is made even worse by the fact that Ms. Geller is now positioning herself to be a defender of free speech, while Mr. Choudary is purporting to speak on behalf of all Muslims."

Conservative media outlets hyped a misleading Breitbart report on an "Islamic Tribunal using Sharia law" in Texas to fear monger that the tribunals could supersede federal law. But the tribunals are completely voluntary and do not override federal law.

Right-wing media attacked a decision to shutter the New York Police Department's (NYPD) ineffective Demographics Unit surveillance program that that profiled local Muslims and subjected them to increased police scrutiny.

Conservative media have rallied behind Ayaan Hirsi Ali, a political activist known for her toxic anti-Islam rhetoric after Brandeis University cancelled plans to grant her an honorary degree. Right-wing media have painted Hirsi Ali as a champion for women's rights, but instead appear to use her views on gender as a rhetorical gateway to attack the religion of Islam and highlight Hirsi Ali's view that Islam is a religion of violence and a "cult of death."

On April 8, Brandeis University announced that it would reverse course in awarding an honorary degree to Hirsi Ali, a visiting fellow at the conservative American Enterprise Institute (AEI) known for her critical views of Islam. The New York Times reported that while Brandeis has invited Hirsi Ali to speak, it could not "overlook that certain of her past statements are inconsistent with" its values, labeling her past statements as the reason it revoked the degree.

Since the announcement, conservative media figures have rushedtodefend Hirsi Ali, some using her life experience to explain away her Islamophobic comments. Weekly Standard editor Bill Kristol called the move an "example of a war on women" and argued that the university had "caved to Muslim thugs." Fox News' Sean Hannity said the university's decision was an "example of left-wing appeasement." On April 10, Fox contributor Monica Crowley asked, "Where are the moderate Muslims? Where are people who, like Ali, have left the faith and are willing to courageously speak about it? And yet when somebody does show the guts and gets out there to do it, this is how they're treated?"

But Hirsi Ali is not moderate in her views of Islam -- once referring to the religion as "a destructive nihilistic cult of death" in a 2007 interview with The London Evening Standard. The New York Timesreports that Hirsi Ali has also "advocated the closing of Islamic schools in the West and said that 'violence is inherent in Islam' and that 'Islam is the new fascism'." In a 2007 Reason interview, she also called for Islam to be militarily crushed and suggested the Constitution should be amended to permit oppression of U.S. Muslims.

Conservative media have greatly enabled anti-Islam propaganda, and have had a significant role in propagating the belief that Islam is a violent religion and is therefore something the United States must fight against. On April 9, Fox host Andrea Tantaros exemplified this when she defended Hirsi Ali by arguing "we are" at war with radical Islam because "they are going to kill us, as the Qur'an states according to Bernard Lewis and many other scholars, they're going to kill us, Sean, until we are all Muslims or ruled by Muslims."

Fox and other conservative voices such as Pamela Geller, Zuhdi Jasser, and the National Review use figures like Hirsi Ali to boost their own anti-Islamic positions as legitimate, giving them cover to continue spreading anti-Muslim hate. Conservative media's rush to uphold Hirsi Ali's story is therefore much more a defense of their own Islamophobic narratives than of Hirsi Ali herself.

Violence against women in any form is a serious issue in many societies, and to limit the discussion by portraying it as a problem specific to the Muslim community, while dehumanizing an entire faith, is irresponsible, inimical to the cause of women's rights, and it is Islamophobic.

As Evelyn Alsultany, author of Arabs And Muslims in the Media and associate professor at the University of Michigan, told Media Matters, Hirsi Ali "has not promoted any kind of true understanding of Islam, but has provided justification for the public and the government to perpetuate racism." Alsultanty explains further:

While she has brought attention to oppression that some Muslim women face, she has done so by simplistically blaming Islam. As a result, she has powerfully contributed to naturalizing the idea that Islam in and of itself is the enemy of democracy and civilization. This idea has serious consequences. It has led to Muslims in the West facing a spectrum of experiences, from hostile questions about their faith to hate crimes. It has provided justification for the U.S. to invade Afghanistan and Iraq, that has negatively impacted the lives of Muslim women through war.

Communications director to the Center for American-Islamic Relations (CAIR) Ibrahim Hooper similarly pointed out that Hirsi Ali's rhetoric hijacks legitimate issues and "demonizes Islam." As Alsultany concludes, "we need to find a way to discuss a serious problem -- violence against women in a way that does not present the problem as exclusive to Muslim women."

Clinging to persecution fantasies that seem to grow darker each year, conservative voices continue to hype doomsday scenarios in which President Obama is scheming to confiscate firearms, socialize American medicine, silence his critics through brute political force, and wage violent class warfare. Allegedly under siege at every turn as their freedoms are stripped away, conservatives embrace an imagined status as perennial victims.

The result? Wallowing in self-pity and convinced of the dark forces moving against them, conservatives launch attack after attack, insisting they're fighting forces at home akin to Hitler's Nazi storm troops. They complain louder and louder that America has become like Nazi Germany under Adolf Hitler when 6 million Jews were murdered during the Holocaust.

Nazi analogies aren't new and conservatives didn't trademark them. But the cries have become far more frequent during Obama's sixth year in office.

Four years ago, Fox News chairman Roger Ailes accused the management of National Public Radio of having "a kind of Nazi attitude" for firing commentator Juan Williams. Former Fox host Glenn Beck frequently immersed himself in offensive Hitler rhetoric during Obama's first years in office, while the then-burgeoning Tea Party movement did the same. And so did Rush Limbaugh, who obsessed over Obama-Nazi comparisons in 2009: "Adolf Hitler, like Barack Obama, also ruled by dictate."

In 2009, the Anti-Defamation League, led by Holocaust survivor Abe Foxman, documented the Tea Party's growing reliance on "Nazi comparisons" as a way to express its anti-Obama rage. Yet today the Nazi claims arrive effortlessly and on a depressingly regular basis as conservatives line up to compare this president, his allies, and this country to one of the worst chapters in civilized history.

The thoughtless rhetoric not only captures how detached Obama's critics have become from reality (not to mention the blanket insensitivity involved), but it also reveals the bizarre view conservatives have of their alleged political strife.

Fox News contributor Dr. Ben Carson recently claimed America is now "very much like Nazi Germany" in that it has a government "using its tools to intimidate the population." Carson defended the insulting comparison by suggesting American conservatives are being targeted and intimidated by the government: "Maybe if I don't say anything, I won't be audited, people won't call me a name."

Audited? Name-calling? Historical note: Those were certainly among the least painful afflictions Jews suffered during the Nazi reign of terror. "I know you're not supposed to say 'Nazi Germany,'" said Carson. "But I don't care about political correctness."

Republican and conservative media figures lauded a report from CBS' 60 Minutes on the September 2012 Benghazi attacks, using it to advance their attacks on the Obama administration and Hillary Clinton. But that report has since come under fire following the revelation that the piece's key Benghazi "eyewitness" had previously claimed he was nowhere near the compound on the night of the attack.

Days after the 1996 Olympic Park bombing, media and federal investigators focused on their top suspect: Richard Jewell, the security guard who had first discovered the bomb which killed one and injured 111. It took more than a year for Jewell to clear his name; he would successfully sue several outlets for their coverage but remained haunted by the memory of the reporters who went after him "like piranha on a bleeding cow" for years.

In the 24 hours following yesterday's tragic bombings at the Boston Marathon, several right-wing media figures have attempted to create their own Jewell. Echoing the same piranha-like voraciousness seen in that case, they have published the name, home address, and what they claim are Facebook pictures of a 20-year-old Saudi national that police have since identified as a witness -- not a suspect -- to the Boston bombings.

Less than two hours after the bombing took place, The New York Post -- citing unnamed "law enforcement sources" -- claimed that a "Saudi Arabian national" was a "suspect" in the case and that he was "under guard at an undisclosed Boston hospital." Several right-wing outlets quickly trumpeted that report. But the claim quickly unraveled (as did the paper's similarly sourced claim that 12 had been killed in the explosions), with law enforcement telling reporters that no one had been arrested in the case and that the Saudi was a witness who was cooperating with authorities.

By the next afternoon, Fox News was reporting that "a federal law enforcement official is confirming... that Saudi man, the college student who was described as a person of interest in the Boston bombings, has now been ruled out as a suspect in this bombing."

But in the interim, the right-wing media -- led by popular conservative blogger Jim Hoft -- swallowed the initial Post report and began posting as much personal information about the man as they could discover.

After the White House released a picture of President Obama skeet shooting at Camp David, conservative bloggers were quick to claim that the photo had been altered or created with Adobe Photoshop or a similar graphics editing program. This follows a long, bizarre tradition of conservative media labeling a wide range of pictures and documents related to the president as fraudulent.

In the past few years, conservatives have accused President Obama and his staff of Photoshopping the short and long-form versions of the president's birth certificate, two separate photos of the president with his family, two Situation Room photos from the day of the bin Laden raid, a photo of Obama throwing a football, and now a photo of the president shooting skeet.

During an interview last month with The New Republic, President Obama was asked if he has ever fired a gun. After the president told the magazine that he goes skeet shooting with guests at Camp David, conservatives -- as well as reporters from more mainstream outlets -- sought proof. In order to quiet the skeptics, on Saturday the White House released a photo of the president shooting clay targets at Camp David in 2012:

Linking to the picture on Twitter, White House senior adviser David Plouffe joked, "let the photoshop conspiracies begin!" While Plouffe was mocking the penchant of some conservatives to turn everything related to President Obama into a conspiracy, some conservative outlets quickly proved his point by doing just that (New YorkMagazine has produced a comprehensive roundup of the skeet shooting conspiracies).

To give you some idea of the level of analysis in the piece, among Harlin's evidence that something is off about the Obama picture is his observation that unlike Obama, "most shooters wear baseball style caps" to help "block unwanted sun in your eyes."

It's easy to point and laugh at analyses like these, but conservatives' obsession with these Photoshop conspiracies shows the type of paranoid nonsense that has passed for journalism at many prominent conservative outlets during the Obama era.

In this report we examine right-wing claims that the president's allies have altered:

Conservative conspiracy theorists have been obsessed with exposing what they see as a series of nefarious secrets hidden in President Obama's past. The idea that Obama has been hiding something has driven years of birth certificate conspiracies, and, most recently, Donald Trump making a very public fool of himself yesterday with his announcement that he was holding a charity donation ransom in exchange for Obama's college transcripts.

One of the more bizarre forms conservatives' sleuthing has taken is their ongoing quest to find Obama's "real" father. According to conservatives, alleged inconsistencies in Obama's biography prove that the elder Barack Obama is not the president's true father (they concede that Obama's mother was in fact Stanley Ann Dunham). Depending on whom you ask, Obama's "real" father could be Malcolm X, "some Indonesian," Frank Marshall Davis, or an unidentified "American black."

While all of these claims are outlandish and discrediting, their originators have nonetheless wielded outsized influence in the right-wing media and conservative movement at large.

On today's edition of Happening Now, Fox News obscured language in Islamophobic billboards created by conservative blogger Pam Geller's American Israel Defense Initiative, deeming the language "so inflammatory we're not going to show it to you." While Fox seems to have finally drawn a line on Geller's bigotry, the network has promoted her for years.

The ads, currently posted in NYC subway stations, read: "In any war between the civilized man and the savage, support the civilized man. Support Israel/Defeat Jihad." Fox blurred the word "savage" when showing the ad to viewers:

The New York Metropolitan Transit Authority initially refused to run the ads, on the grounds that it violated their policy against accepting advertising that demeans individuals or groups on the basis of race, color, religion, national origin. Geller's group sued the MTA and in July a federal judge ordered the agency to run the ads, saying that the content was protected speech.

The New York Times was forced to issue two corrections after relying on Capitol Hill anonymous sourcing for its flawed report on emails from former Secretary of State and Democratic presidential candidate Hillary Clinton. The Clinton debacle is the latest example of why the media should be careful when relying on leaks from partisan congressional sources -- this is far from the first time journalists who did have been burned.

Several Fox News figures are attempting to shift partial blame onto Samuel DuBose for his own death at the hands of a Cincinnati police officer during a traffic stop, arguing DuBose should have cooperated with the officer's instructions if he wanted to avoid "danger."

Iowa radio host Steve Deace is frequently interviewed as a political analyst by mainstream media outlets like NPR, MSNBC, and The Hill when they need an insider's perspective on the GOP primary and Iowa political landscape. However, these outlets may not all be aware that Deace gained his insider status in conservative circles by broadcasting full-throated endorsements of extreme right-wing positions on his radio show and writing online columns filled with intolerant views that he never reveals during main stream media appearances.